In image reproduction systems, such as photography and thermal printing, receiver media is tightly held to a rotating drum. It is desirable to clamp both the top or leading edge and bottom or trailing edge of the receiver media against the rotating drum to produce a crisp image. It is also important that the reproduction apparatus conserve space. Toshifumi Kato U.S. Pat. No. 4,390,176 which issued Jun. 28, 1983, discloses a sheet clamping device which is used to clamp both the leading and trailing ends of a receiver sheet while the sheet is disposed around the peripheral surface of a drum rotating in a given direction. The sheet clamping device uses cams and levers to engage and disengage the receiver media which makes the device bulky. Accordingly, it will be appreciated that it will be highly desirable to have a sheet clamping apparatus which is simple in construction and conserves space.
In conventional digital image recorders, spring loaded piano type hinge clamps have been successfully used. Unfortunately, the same piano type hinge is unsuitable for a small diameter drum because, on a small diameter drum, a large percentage of lost space around the circumference exists. The wasted space exists because of the space required for actuation and spring levers used with the hinge. It is desirable to have a photographic material clamp that clamps both the top and bottom ends of the receiver sheet while occupying a minimal amount of the circumferential area of the drum. It is also desirable to have a photographic material clamp which does not have levers, cams and springs external to the drum and which would conserve space.